The invention relates to a liquid filled container referred to as a xe2x80x9cwater globexe2x80x9d or xe2x80x9csnow globexe2x80x9d; and more particularly, to an improved sealing plug for such a container.
A conventional water globe is illustrated in FIG. 1 and comprises a transparent crystalline spherical globe 10 that has a large circular opening 12 at the bottom thereof with an extended cylindrical skirt 14. The globe is filled with a liquid, primarily water sometimes including an alcohol anti-freeze mixture, and is sealed at the skirt with a hollow cylindrical rubber plug 16. The plug has a cylindrical wall 18 and a circular flat upper surface 20 that supports a small decorative ornament 22 within the globe. By means of the water and the convex lens effect of the sphere, the small ornament within the water globe generates an enlarged view that appears to fill the globe. The ornament is typically mounted on a plastic disc 24 that is securely glued to the upper surface of the plug. The liquid usually further includes tiny suspensible particles 26, so that when the globe is shaken, the particles are dynamically suspended in the liquid and momentarily provide the illusion of a snowy scene around the ornament. Some snow globes include motors or pumps to continuously move the ornament or agitate the fluid to provide an interesting display.
The water globe is typically produced utilizing a large liquid filled tank. The globe is inverted over the tank and the suspensible particles are inserted into the globe; the globe is then submersed and filled with the liquid; while submersed, the ornament/plug assembly is inserted into the skirt of the opening, without entrapping any air bubbles. The filled globes are then removed from the tank, turned right side up and supported on the base 28 of the skirt, or further mounted into an ornamental base 30. The inner wall of the skirt of the globe usually has an annular concave contour 32, and the wall of the plug has a complementary convex contour to retain the plug within the skirt with a watertight seal.
Any air bubbles discovered within the filled globe during production are considered unacceptable and the finished part is rejected, scraped, or reworked. Any air bubbles that occur after shipment may render the globe impossible to sell or result in a dissatisfied customer. A particular problem can occur due to temperature and volume changes that effect the pressure of the liquid within the globe. Water has an expansion relationship V2=0.00115 V1 xcex94t; and a pressure relationship P1 V1/T1=P2 V2/T2, and for a globe having a fixed volume where V1=V2, then P2=P1 T2/T1. The globes are usually sealed at a temperature of about 25xc2x0 C. However, during shipment, the globes may experience multiple temperature swings whereby high temperatures causes the internal pressure to increase, colder temperatures causes the internal pressure to decrease, and freezing temperatures also cause the volume to expand. The upper surface 20 of the conventional rubber plug 16 is thick and stiff, and the plastic disc 24 bonded thereto results in a very rigid seal, and therefore, the globe has a confined, fixed volume. During thermal expansion of the liquid within the fixed volume, the internal pressure can force a small quantity of liquid around the wall of the sealing plug and out of the container. The seal otherwise remains watertight; however, when the temperature is subsequently lowered, the liquid volume decreases (and is minimized at about 4xc2x0 C.) creating a slight negative pressure or vacuum within the container, and in some cases air is drawn around the wall of the plug into the globe to balance the pressure. Once inside the container, the air bubbles cannot be easily removed and float to the top of the globe resulting in an unacceptable appearance.
In view of the foregoing, it is an object of the present invention to provide a means to normalize the pressure within a water globe during changes in internal volume and prevent the formation of air bubbles within the globe.
It is another object to provide a sealing plug that can expand and contract with changes in volume of the liquid within a water globe and prevent the formation of air bubbles within the globe.
The foregoing objects are accomplished by an improved sealing plug for a water globe having a lower opening therein with an extended skirt thereon, having a fixed peripheral portion for sealing the container and supporting an object within the container and having a flexible diaphragm adapted to adjust for changes in volume and pressure of the water within the globe. The plug comprises a peripheral wall adapted to sealingly engage the skirt of the globe having an upper end thereof with two or more supports extended upward therefrom for supporting an object within the container, and a flexible diaphragm having an upper surface and a recessed channel around the periphery thereof connected to the wall and extending across the upper end of the wall.
In another embodiment, the diaphragm of the sealing plug further includes an aperture therein, for sealingly engaging an object extended through the plug into the globe.